Hardness measurement reagent

Abstract

To provide a hardness measurement reagent unaffected by an M alkalinity in hardness measurement. A hardness measurement reagent as a one-solution type reagent includes a dye chosen from Eriochrome Black T (EBT) and Calmagite, triethanolamine, a glycol compound, and a pH buffer, in which the pH buffer includes a combination of amines selected from primary amines and secondary amines and a salt of a weak base.

1. A hardness measurement reagent as a one-solution type reagent, comprising: a dye chosen from Eriochrome Black T (EBT) and Calmagite; triethanolamine; a glycol compound; and a pH buffer,
 wherein the pH buffer comprises a combination of (i.) amines chosen from primary amines and secondary amines and (ii.) a salt of a weak base. 
 
     
     
       2. A hardness measurement reagent according to  claim 1 , wherein the salt of a weak base comprises a salt selected from the group consisting of an ammonium salt, a primary amine salt, and a secondary amine salt. 
     
     
       3. A one-solution type hardness measurement reagent comprising: a dye chosen from Eriochrome Black T (EBT) and Calmagite; triethanolamine; a glycol compound; a pH buffer; a sensitizer; and an antifoaming agent,
 wherein the pH buffer comprises a combination of (i.) amines chosen from primary amines and secondary amines and (ii.) a salt of a weak base. 
 
     
     
       4. The one-solution type hardness measurement reagent of  claim 3 , comprising Eriochrome Black T, triethanolamine, ethylene glycol, EDTA-Mg as a sensitizer, polyoxyethylene octylphenyl ether as an antifoaming agent, and a pH buffer comprising monoethanolamine and ammonium chloride. 
     
     
       5. A one-solution type hardness measurement reagent comprising: (a) a dye selected from the group consisting of Eriochrome Black T (EBT) and Calmagite; (b) triethanolamine; (c) a glycol compound selected from the group consisting of ethylene glycol, propylene glycol, and diethylene glycol; and (d) a pH buffer,
 wherein the pH buffer comprises a combination of (i.) amines chosen from primary amines and secondary amines and (ii.) a salt of a weak base.